Process for treating wool for anti-felting purposes



United States Patent 3,220,086 PROCESS FOR TREATING WOOL FORANTI-FELTING PURPOSES George Henry Taylor, Rothley, Jack H. Rowlett,Oadby, and Derek Bradley, Loughborough, England, assignors to Foister,Clay 8: Ward Limited, Leicester, England, a British company No Drawing.Filed Apr. 11, 1963, Ser. No. 319,912 Claims priority, application GreatBritain, Apr. 14, 1962, 14,509/ 62 19 Claims. (Cl. 28-76) (Filed underRule 47(a) and 35 U. S. C. 116) The present invention relates to amethod of producing all classes of wool knitwear, which expression isused in a generic sense and is intended to cover, not only hosieryincluding say, socks (sox), half-hose, three-quarter hose, and sportshose, but also various other knitted garments and articles of wearingapparel including fullfashioned outerwear and underwear, and cutouterwear and underwear made on flat or circular machinesall knittedfrom wool or a preponderance of wool.

The object of the invention is to provide a method of producing woolknitwear which can be satisfactorily washed over and over again in awashing machine without either the appearance of the fabric or theserviceability of the articles being in any way adversely affected.Heretofore, the continual washing of such goods made of wool in awashing machine has not been possible without undue distortion, pilling,shrinkage and felting of the knitted fabric.

In particular, an aim is to minimise the total of the relaxationshrinkage plus the milling shrinkage to as little as under the figure ofin the case of footwear, and 5% area shrinkage in the case of garments,after washing 5 hours in a washing machine.

The improved method of this invention comprises knitting wool knitwearmore tightly than usual with yarn consisting of or including wool andhaving a higher or tighter twist than normal, and treating the wool foranti-shrink purposes in a process which subjects it to a higher degreeof chemical anti-felting treatment than is normally the case.

The treatment of the wool may be carried out either by treating thegoods after fabrication, or by treating the yarn before knitting or thewool before spinning.

Turning to the characteristic step of knitting the wool knitwear moretightly than usual. This means that the stitch length knitted with anyparticular count of yarn on any of the different gauges of machines isless than would be knitted normally. Due to the fact that it is possibleto knit both a wide range of stitch lengths and counts on any gauge ofmachine, it is essential that some means of relating the desiredresultant fabric with a stitch length and count of yarn be found; thisrelationship is provided for in the term Cover factor which is now usedin the hosiery industry and is defined as:

1 Stitch length count Cover factor the purpose of the present inventionthe cover factor adopted is in excess of this viz. 1.32 upwards.

For fabrics knitted on two sets of needles, that is to say all rib andinterlock structures, the normal cover factor range is of the order of1.29-1.41, but for the purpose of this invention a cover factor upwardsof 1.42 is adopted.

An example illustrating the comparison between a fabric having a normalcover factor and one knitted to give a higher cover factor is to befound in the production of half-hose made from Wool with a Bradfordworsted count of 2/ 27 /2, on a 12 gauge circular half-hose machine of4" diameter and equipped with 168 needles. In this case the tight stitchlength would be 0.1965", derived from a course length of 33", thisgiving a cover factor of 1.377; in normal knitting, on the other hand,the length of yarn per course would be 35" giving a substantially longerstitch length of 0.2083" and a cover fact-or of 1.31.

Another example of this increase in cover factor is given by fabricsproduced on a 27 gauge full-fashioning machine. Using a 2/ 32s Worstedyarn, a normal fabric having a cover factor of 1.19 would be obtained byknitting a stitch length of 0.21". To produce a fabric in accordancewith the invention it is necessary to knit a stitch length of at least0.1893", which gives a cover factor of 1.32; a more desirable fabric maybe obtained by knitting a stitch length of 0.1780" and this gives acover factor of 1.402.

A further example of the invention is to be found in the production ofrib fabrics made from 2/ 32s worsted yarn on a 12 gauge circular ribmachine. In this instance, a normal fabric having a cover factor of 1.38is knitted with a stitch length of 0.1812"; whereas a suitable fabricmay, in accordance with this invention, be produced having a coverfactor of 1.545 by knitting a stitch length of 0.1619". The minimumconditions for this fabric would be a stitch length of 0.1761", giving acover factor of 1.42.

As regards the higher or tighter twist of the yarn employed in theimproved method; this is achieved by increasing the turns per inch in asingles yarn and also the turns per inch in both the singles and foldingtwists of a two-fold yarn above that normally used in a hosiery yarn.For example, in the case of a normal singles, 64s quality wool hosieryyarn of 1/27 /2 Bradford worsted count, this can have a twist of 11turns per inch which is arrived at by the simple formula:

count Turns per inch= In the improved method the singles twist isincreased to that given by the formula:

count 5 6 A most important feature of the present invention is that thefolding twist of the selected two-fold yarn can ideally be the same asthat used in the singles components, but the minimum conditions at whichthe invention will work is for the folding twist of the twofold yarn tobe of the twist in the single components.

Turns per inch (folding) An example of this is seen in the production offully fashioned knitwear on a 27 gauge full-fashioning machine using atwo-fold yarn having 13 turns per inch in the singles components and(ideally) also 13 turns per inch in the folding; however, the minimumfolding twist would be 9% turns per inch based on a 64s quality woolyarn of Bradford worsted count 2/ 32s.

A further example is in the production of wool half hose on a 168needle, 12 gauge, 4" diameter machine using a 64s quality woolyarn. Iftwo single ends of 27 /2 Bradford worsted count are used, the turns perinch will be 11% in each yarn; if 2/27 /2 Bradford worsted count yarn isused the turns will be 11% turns per inch inthe singles components and(ideally) 11% in the folding, although a minimum folding twist would be8.8 turns per inch.

Finally, treating the wool in such .a way as to subject to a higherdegree of chemical anti-felting treatment than is normally the casemeans that the said wool is treated for anti-felting purposes in achemical anti-felting process in which the concentration of the reagentsused 'is greater than is normally applied.

For example, in anti-felting processes employing chlorine as the activereagent, which may be applied either directly to the wool, or byliberation from chlorine-containing compounds-either alone or in thepresenceof other compounds, the percentage of chlorine which is usuallyapplied is in the/range of 22 /z%. For the purpose of this invention theamount of chlorine applied to the wool will be at least 3%.

Method of testing The aforementioned ranges of twists, cover factors andpercentages of chemical anti-felting treatment were de termined by testscarried out in a 1952 model Hoover washing machine with the impellerspeed reduced to 460 rpm. and having an inside size of 29 cms. x 35 cms.x 34 cms. deep. 30 litres of 0.5% soap solution (using water of Zerohardness) were used at 85 C. and the total weight of the goods undertest was made up to 2 lbs. The duration of each test was 3 hours.

The actual method of preparing samples and the measurement of relaxationand milling shrinkageis laid down in British Standard No. 1955:1953.

The normal'cover factor range is specified in the Journal of the TextileInstitute, vol. 53, p. 630'.

'We claim:

1. A methodof producing wool knitwear comprising the steps of (a) soknitting the knitwear of a two-fold wool yarn comprising two singlescomponents on a knitting machine of a selected gauge that the resultantcount of the said yarn and the length of the stitches formed therefromgives a cover factor (count+8) 3 and the folding twist of said yarnbeing at least 75% of the twist in the singles components, and (b)treating the wool for anti-felting purposes in a chemical anti-feltingprocess in which chlorine is used as the active reagent and in which theconcentration of available chlorine is at least 3% of the dry weight ofthe wool in the fabric.

2. A method of producing wool knitwear comprising the steps of (a) soknitting the knitwear of a singles yarn comprising wool on a knittingmachine of a selected gauge that the resultant count of the said yarnand the length of the stitches formed therefrom gives a cover factorcover factor: stitch length X x count exceeding 1.32 for a fabricknitted on one set of needles and 1.42 in respect of a fabric knitted ontwo sets of needles, the twist in turns per inch of the singles yarnbeing given by the formula (count+8) 3 (count+8) 3 the said yarn beingso knitted on a knitting machine of a selected gauge that the resultantcount of the yarn and the length of the stitches formed therefrom givesa cover factor 1 cover f actor stitch length X y count exceeding 1.32for a fabric knitted onone :set of needles only and 1.42 in respect of afabric knitted on two sets of needles, and (b) treating the wool foranti-felting purposes in a chemical anti-felting process in whichchlorine is used as the active reagent and in which the concentration ofvailable chlorine-is at least 3% of the dry weight of the wool in thefabric.

4. A method according to claim .3, wherein the said treatment of thewool is carried out bytreating the goods, .after fabrication,foranti-shrink purposes.

5. A method according to claim 3, wherein the said treatment of the woolis carried out by treating the yarn prior to knitting.

6. A method according to claim 3, wherein the said treatment of the wooltakes place before it is spun into the said'yarn.

7. A method of producing wool half-hose comprising the steps'of (a) soknitting the half-hose of a two-fold yarn having a Bradford worstedcount of 2/ 27 /2 on a 12 gauge circular half-hose machine having aneedle cylinder of 4" diameter and equipped with 168needles as toproduce a stitch length of 0. 1965", derived from a course length of 33"and giving a cover factor cover faotor=- stitch lengthXw/count of 1.377,the twist in turns per inch of each singles component of the saidtwo-fold yarn being given by the formula (count+8) 3 and thefoldingtwist of the yarn being atleast of the twist in the singlescomponents, and (b) treating the wool for anti-felting purposes in achemical, anti-felting process in which chlorine .is used as the activereagent and in which the concentration-of available chlorine is at least3% of the dry weight of the wool in the fabric.

8. A method of producing wool fabric comprising the steps of (a) soknitting the fabric of a two-fold wool yarn having worsted count of2/32s on .a 27 gauge fullfashioning machine as to produce a stitchlength of at least 0.1893" giving a cover factor stitch lengthXVcount of1.32, the twist in turns per inch of each singles component of the saidtwo-fold yarn being given by the formula cover fact0r= (count-k8) 3 andthe folding twist of the yarn being at least 75% of the twist in thesingles components, and (b) treating the wool for anti-felting purposesin a chemical anti-felting process in which chlorine is used as theactive reagent and in which the concentration of available chlorine isat least 3% of the dry weight of the wool in the fabric.

9. A method as claimed in claim 8, which is modified to knit a stitchlength of 0.1780" and give a cover factor of 1.402.

10. A method of producing a wool rib fabric comprising the steps of (a)so knitting the fabric of a two-fold wool yarn having a worsted count of2/ 32s on a 12 gauge circular rib machine as to produce a stitch lengthof 0.1619 giving a cover factor stitch length X V count cover factor:

(count-F8) 3 and the folding twist of the yarn being at least 75% of thetwist in the singles components, and (b) treating the wool foranti-felting purposes in a chemical anti-felting process in whichchlorine is used as the active reagent and in which the concentration ofavailable chlorine is at least 3% of the dry weight of the wool in thefabric.

11. A method of producing a wool rib fabric comprising the steps of (a)so knitting the fabric of a two-fold wool yarn having a worsted count.of 2/ 32s on a 12 gauge circular rib knitting machine as to produce astitchlength of 0.1761 giving a cover factor 1 stitch length X count of1.42, the twist in turns per inch of each singles component of the saidtwo-fold yarn being given by the formula cover factor= the twist in thesingles components, and (b) treating the wool for anti-felting purposesin a chemical anti-felting process in which chlorine is used as theactive reagent and in which the concentration of available chlorine isat least 3% of the dry weight of the wool in the fabric. 12. A method ofproducing fully-fashioned knitwear comprising the steps of (a) soknitting the fabric of a two-fold 64s quality wool yarn of Bradfordworsted count 2/ 32s having 13 turns per inch in the singles componentsand a folding twist of anything from 9% to 13 turns per inch on a 27gauge full-fashioning machine as to produce a stitch length of at least0.1893" giving a cover factor stitch lengthXx/count of 1.32, and (b)treating the wool for anti-felting purposes in a chemical anti-feltingprocess in which chlorine is used as the active reagent and in which theconcentration of available chlorine is at least 3% of the dry weight ofthe wool in the fabric.

cover factor 13. A method as claimed in claim 12, which is modified toknit a stitch length of 0.1780" and give a cover factor of 1.402.

14. A method of producing wool half-hose Comprising the steps of (a) soknitting the half-hose of a two-fold 64s quality wool yarn of Bradfordworsted count 2/ 27 /2 having 11% turns per inch in the singlescomponents and a folding twist of anything from 8.8 to 11% turns perinch on a 12 gauge circular half-hose machine having a needle cylinderof 4" diameter equipped with 168 needles that the aforesaid count of theyarn and the length of the stitches formed from the said yarn gives acover factor 1 stitch lengthXx/count exceeding 1.32, and (b) treatingthe wool for anti-felting purposes in a chemical anti-felting process inwhich chlorine is used as the active reagent and in which theconcentration of available chlorine is at least 3% of the dry weight ofthe wool in the fabric.

15. A method of producing wool half-hose comprising the steps of (a) soknitting the half-hose of a yarn comprising two ends of 1/27 /z Bradfordworsted count 64s quality wool having 11% turns per inch in each end ona 12 gauge circular half-hose machine having a needle cylinder of 4"diameter and equipped with 168 needles that the aforesaid count of theyarn and the length of the stitches formed from the said yarn gives acover factor stitch length V count exceeding 1.32, and (-b) treating thewool for anti-felting purposes in a chemical anti-felting process inwhich chlorine is used as the active reagent and in which theconcentration of available chlorine is at least 3% of the dry weight ofthe wool in the fabric.

16. A method of producing wool knitwear comprising the steps of (a) soknitting the knitwear of a two-fold wool yarn comprising two singlescomponents on a knitting machine of a selected gauge that the resultantcount of the said yarn and the length of the stitches formed therefromgives a cover factor 1 stitch length X count exceeding 1.32 for a fabricknitted on one set of needles only and 1.42 in respect of a fabricknitted on two sets of needles, the twist in turns per inch of eachsingles component of the said two-fold yarn being given by the formulacover factor cover factor:

cover factor= (count-t8) 3 and the folding twist of said yarn being atleast 75% of the twist in the singles components, and (b) treating thewool for anti-felting purposes in a chemical anti-felting process inwhich chlorine is used as the active reagent and is applied directly tothe wool, the percentage of such chlorine present in the process beingat least 3%.

17. A method as claimed in claim 16, which is modified by application ofthe chlorine to the wool by liberation from chlorine-containingcompounds.

18. A method of producing wool knitwear comprising the steps of (a) soknitting the knitwear of a singles yarn comprising wool on a knittingmachine of a selected gauge that the resultant count of the said yarnand the length of the stitches formed therefrom gives a cover factorcover factor= stitch lengthX count 7 8 needles, the twist in turns perinch of the singles yarn References Cited by the Examiner being given bythe form la UNITED STATES PATENTS 1,522,555 1/1925 Trotman 8-128 3 53,100,674 8/1963 Steiger 8127.6

and (b) treating the wool for anti-felting purposes in a chemicalanti-felting process in which chlorine is used OTHER REFERENCES as theactive reagent and is applied directly to the wool, Moncrietf, WoolShrinkage and Its Prevention, The the percentage of such chlorinepresent in the process London Trade Press Ltd, copyrighted 1953, pages488 being at least 3%. 10 and 489.

19. A method as claimed in claim 18, which is modified by application ofthe chlorine to the wool by libera- DONALD W. PARKER, Primary Examiner.tion from chlorine-containing compounds.

1. A METHOD OF PRODUCING WOOL KNITWEAR COMPRISING THE STEPS OF (A) SOKNITTING THE KNITWEAR OF A TWO-FOLD WOOL YARN COMPRISING TWO SINGLESCOMPONENTS ON A KNITTING MACHING OF A SELECTED GAUGE THAT THE RESULTANTCOUNT OF THE SAID YARN AND THE LENGTH OF THE STITCHES FORMED THEREFROMGIVES A COVER FACTOR COVER FACTOR= 1/STITCH LENGTH X (COUNT)(**1/2)EXCEEDING 1.32 FOR A FABRIC KNITTED ON ONE SET OF NEEDLES ONLY AND 1.42IN RESPECT OF A FABRIC KNITTED ON TWO SETS OF NEEDLES, THE TWIST INTURNS PER INCH OF EACH SINGLES COMPONENT OF THE SAID TWO-FOLD YARN BEINGGIVEN BY THE FORMULA (COUNT + 8)/3 AND THE FOLDING TWIST OF SAID YARNBEING AT LEAST 75% OF THE TWIST IN THE SINGLES COMPONENTS, AND (B)TREATING THE WOOL FOR ANTI-FELTING PURPOSES IN A CHEMICAL ANTI-FELTINGPROCESS IN WHICH CHLORINE IS USED AS THE ACTIVE REAGENT AND IN WHICH THECONCENTRATION OF AVAILABLE CHLORINE IS AT LEAST 3% OF THE DRY WEIGHT OFTHE WOOL IN THE FABRIC.